I. Field of the Present Invention
The present invention relates generally to electrical motor apparatus, and more particularly, to a starter motor having a stator winding fixedly secured within the housing and a rotor winding mounted on a rotatable shaft in the housing within the stator winding.
II. Description of the Prior Art
Starter motors are well known devices for initiating operation of a turbine engine such as those used in aircraft. A starter motor typically includes a shaft rotatably mounted in a housing and having a rotor winding secured thereto for rotation therewith. The rotor winding is positioned within a circumferential stator winding. The housing encloses the windings and other electrical components in order to protect them from environmental conditions and debris. Quite often the housing is generally cylindrical and closed at both ends so that only an end of the shaft extends outwardly from a starter motor, whereby the shaft can be coupled by a mechanism to the turbine shaft.
In previously known starter motors, the power output of the motor is determined by the size and construction of the windings in the motor. Thus, the windings and the magnetic cores associated therewith determine the size of the housing which is necessary to enclose these parts. On the other hand, it is advantageous to minimize the size and weight of any component carried by an aircraft. Thus, a housing construction primarily designed for enclosing the electrical components of the starter motor can result in a starter motor which is extremely large and bulky. Such a motor presents problems in positioning and supporting the starter motor, and can have a significant effect upon size, weight and handling characteristics of an aircraft.